The present invention relates to a new and improved construction of a comminuting machine.
In its more particular aspects, the present invention specifically relates to a new and improved construction of a comminuting machine for comminuting waste material which may be intended to be composted. Generally, such machines are mounted at a mobile support frame and comprise a housing in the form of a container for receiving the material to be comminuted. A conveyor is disposed in the housing or container for conveying the infed material to a rotary impact mechanism. The rotary impact mechanism cooperates with an impact plate in a comminuting section which precedes a discharge opening of the housing or container for discharging the comminuted material under the action of the rotary impact mechanism. The impact plate may be followed by further comminuting means through which the comminuted material is discharged with further comminution. The comminuted material may be deposited in stacks or pits for composting.
A comminuting machine or composting equipment such as known, for example, from U.S. Pat. No. 4,852,816, granted on Aug. 1, 1989 to the applicant of the instant application, is constructed for comminuting organic or wood waste originating in forestry, municipality or building operations. A trough-shaped container receives the material to be comminuted, for example, by means of a shovel loader. Infeed means are provided in the form of an infeed conveyor which is located above the bottom of the container and feeds the material to a rotary impact mechanism. The rotary impact mechanism drives the infed material through an entrance gap defined between an impact ledge and rotating flails of the rotary impact mechanism. The impact ledge is followed by retainer claws which extend between adjacent ones of the rotating flails for comminuting the material which has been forced through the entrance gap. An impact plate follows the retainer claws and has teeth protruding toward the rotating flails and cooperating therewith for further comminuting the material prior to its discharge through a discharge opening from a rear part of the container.
In a further development (Doppstadt shredder, type AK 330) of the aforementioned comminuting machine, the infeed means or apparatus include an infeed conveyor in the form of a scraper conveyor acting from below on the infed material and a revolving heavy-weight intake roll which bears upon the infed material for conveying the same to the entrance gap. The entrance gap is defined by an impact ledge and the rotary impact mechanism. The entrance gap is followed by an impact plate containing two plate sections. The two plate sections are arranged at an angle with respect to each other so that the impact plate extends along an upper part of the cylindrical action area of the rotating flails. Teeth protrude from the impact plate toward the rotating flails and are arranged in parallel rows transverse with respect to the rotational direction of the rotating flails, the rows of teeth being transversely offset from each other. There is thus defined a throughpass gap through which the incoming material is forced under the action of the rotating flails and subjected to comminuting action. The impact plate is followed by a discharge opening and, if desired, further comminuting means. A prime mover like a diesel engine drives the rotary impact mechanism through an overload coupling such as a fluid or hydrodynamic coupling. Such coupling mainly serves to dampen rapid transient variations in the rotational speed of the rotary impact mechanism in order to prevent such variations from affecting the prime mover. Also driven by the prime mover is a main hydraulic pump like an axial piston pump which supplies pressure fluid to pressure fluid operated components of the comminuting machine such as infeed drive means driving the infeed means or apparatus. Overload control means are additionally provided for controlling the conveying rate of the infeed means as a function of the rotational speed of the rotary impact mechanism, particularly by decelerating or eventually shutting off the infeed drive means in the presence of an excessive load at the rotary impact mechanism.
In both of the aforementioned comminuting machines the impact plate as well as the further comminuting means, if present, are pivotably supported so as to pivot away from the rotating flails in the event that the infed material contains pieces of material which do not disintegrate under the action of the rotating flails in cooperation with the impact plate. The rotary impact mechanism and the impact plate are thus prevented from damage by pieces of non-disintegratable material.
Furthermore, both of the aforementioned comminuting machines are mobile machines in which the container is mounted at a support frame on wheels. Such wheel support can be provided by supporting the comminuting machine on a truck such as known from European Patent No. 0,212,194, the grant of which to the applicant of the instant application was published on Oct. 11, 1987; in such construction the engine of the truck also serves to drive the comminuting machine. The wheel-supported support frame may also carry a power unit for operating the comminuting machine. The power unit is placed at a support frame end remote from the rotary impact mechanism and outside of the trough-shaped container below a protective shield extending therefrom. As described in the aforementioned U.S. patent, such comminuting machine may be displaced at the given working location by means of the shovel loader used for charging the comminuting machine. The support frame may also be supported at a tandem axle. Pressure fluid operated drive means acting upon the front wheels of the tandem axle may be provided for displacing the comminuting machine at the working location (Doppstadt shredder AK 330). Remote control means may be used for controlling the operation of the comminuting machine including the pressure fluid operated drive means. While the machine can be operated in this manner independent of a truck, travel to a different working location requires connection to a towing vehicle like a tractor or truck.
A stationary comminuting machine such as known, for example from German Published Patent Application No. 2,902,257 published on Jul. 31, 1980 is intended for comminuting particularly confidential files but also waste materials of any kind including waste wood. Infeed means like infeed rolls feed the material to an inlet gap and into the interior of a drum-like housing. Parts of the infed material protrude through the inlet gap and are severed or chopped off by a rotary impact mechanism. Following the inlet gap, the drum-like housing accommodates a basically segment-shaped impact body defining a throughpass gap in cooperation with the rotary impact mechanism. The throughpass gap narrows from the inlet gap to an outlet and extends around the upper half of the rotary impact mechanism. The impact body is mounted at the drum-like housing by means of bolts permitting adjustment of the impact body in radial direction relative to the rotary impact mechanism. At its rear end, as viewed in the rotational direction of the rotary impact mechanism, the impact body bears upon a stop. The impact body is provided on its inner side with, for example, a saw-tooth profile which extends parallel to the axis of the rotary impact mechanism. The impact body is followed, in the rotational direction of the rotary impact mechanism, by grate means which extends around the lower half of the rotary impact mechanism and defines a throughpass gap which narrows in the rotational direction.
Contrary to the first mentioned mobile waste comminuting machines, the last mentioned stationary comminuting machine is not provided with any means permitting the impact body and other structures which cooperate with the rotating hammers, to yield in the presence of non-disintegratable material.
Regarding the aforementioned mobile waste comminuting machines, it has been found that the impact ledge suffers rapid wear and thus needs relatively frequent replacement. Also, there exist problems regarding the accommodation of the pressure fluid operated drive motor for driving the infeed means or apparatus.